In the human knee, the anterior and posterior cruciate ligaments (i.e., the ACL and PCL) extend between the top end of the tibia and the bottom end of the femur. These ligaments play an important role in providing both static and dynamic stability to the knee. Often, the anterior cruciate ligament (i.e., the ACL) is ruptured or torn as a result of, for example, a sports-related injury. Consequently, various surgical procedures have been developed for reconstructing the ACL so as to restore stable function to the knee.
For example, the ACL may be reconstructed by replacing the ruptured ACL with a synthetic or harvested graft ligament. More particularly, with such procedures, bone tunnels are typically formed in the top end of the tibia and the bottom end of the femur, with one end of the graft ligament being positioned in the femoral tunnel and with the other end of the graft ligament being positioned in the tibial tunnel. The two ends of the graft ligament are anchored in place in various ways well known in the art so that the graft ligament extends between the tibia and the femur in substantially the same way, and with substantially the same function, as the original ACL.
In some circumstances, the graft ligament may include a bone block connected to one of its ends. This bone block may be used to attach the ligament graft to the patient's femur.
For example, in one well-known procedure, the bone block is placed in the femoral tunnel and then fixed in place using a so-called "Kurosaka" screw. More particularly, with this procedure, a screw is screwed into the bottom end of the femur so that the screw extends parallel to the bone tunnel and simultaneously engages both the bone block and the femur. This screw then keeps the bone block (and hence the graft ligament) secured to the femur.
More recently, interest has developed in procedures for pinning the bone block to the femur by passing a screw through the femur and the bone block so that the screw extends transverse to the bone tunnel. See, for example, U.S. Pat. Nos. 4,901,711; 4,985,032; 5,067,962; 5,152,764; 5,350,380; 5,354,300; 5,397,356; and 5,431,651.
Unfortunately, however, the various apparatus and methods disclosed in the foregoing patents suffer from a variety of deficiencies.
Furthermore, in some circumstances, the graft ligament may not have a bone block attached to one of its ends. In this situation, it can be difficult to securely attach the graft ACL to the patient's femur.
In this latter respect, some work has been done to pass a pin through the femur so that the pin extends transverse to the bone tunnel; the graft ACL is then looped over the pin to secure it to the femur. See, for example, U.S. Pat. Nos. 5,266,075 and 5,393,302.
Unfortunately, however, the various apparatus and methods disclosed in the foregoing patents also suffer from a variety of deficiencies.
Still other art of interest is shown in U.S. Pat. Nos. 3,973,277; 5,004,474; 5,147,362; 5,356,435; and 5,376,119.